


An Exorcist's Best Friend

by Leonawriter



Category: Ao no Exorcist | Blue Exorcist
Genre: Alternate Universe - Werewolf, Fluff and Angst, Gen, first chapter has the most angst
Language: English
Status: In-Progress
Published: 2014-05-08
Updated: 2014-05-08
Packaged: 2018-01-24 00:59:12
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,863
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1585832
Author URL: https://archiveofourown.org/users/Leonawriter/pseuds/Leonawriter
Summary: <blockquote class="userstuff">
              <p>Sometimes believing that the worst outcome is always yours can lead to some anticlimactic moments. Although to be fair, Yukio had every right to believe that turning into a werewolf would mean danger... and instead, they get a bundle of easily intimidated wolf cub.</p>
            </blockquote>





	An Exorcist's Best Friend

He’d been part of a team sent out to deal with a problem reported in the forest. The plan they’d drawn up had been a good one, flexible enough to account for most eventualities. They’d headed in, making as little noise as they could in the hopes of luring the demon out while keeping the element of surprise.

It had worked, but only to a point. The actual fight turned out to be messy – no one had expected a wolf, and the two aria who were in the team had been at a loss to what its fatal verse might be, until Yukio had hazarded a guess and used a silver round.

The demon had cried out in pain, alerting them to the fact that ti was, in fact, a _werewolf_ , allowing the aria to figure out what to recite. It also, however, made the wolf demon angry, since the injury hadn’t been enough to put it down.

It was powerful, knocking over their knight and sending one of the aria flying. It almost did the same to him, but Yukio had twisted at just the right moment and kept his balance enough to get a last shot in before the remaining aria finished off the verse, leaving them with one unmoving and still wolfish body to deal with.

It wasn’t until they’d made their way back to the academy and were being treated for their various injuries that he realised that he’d been scratched.  Three gashes, not as bad as they looked or as deep, running across his left shoulder.

He sighed as bandages were applied and vaccines administered, knowing that once the adrenaline wore off it would start hurting like hell if he didn’t have painkillers, and he’d have trouble using that arm for a while, too.

Still, he’d prefer an arm temporarily out of action over not being able to use it at all, or the loss of his life, and that of others. The only thing he was really bothered by was the fact that the wolf, if he was correct… had used to be a person.

Someone they hadn’t been able to save.

It’d been too late. Perhaps if they’d got there sooner, or before the curse had time to settle… but even then, chances were that whatever they’d done wouldn’t have been enough, and things would have ended this way anyway.

He started back towards the dorm, good hand covering his mouth to hide a yawn as he realised what kind of time it was – Rin would, or should, be asleep by now, so at least he didn’t have to explain the injury just yet, and maybe wouldn’t have to for a while, if he woke up and left early in the morning.

He woke up the next morning from a dreamless, if not entirely restful, sleep, and didn’t waste time in filling out the report that should have been finished after the mission, but had been put on hold due to the late hour.

He added that he was injured, but that it shouldn’t hinder him too much as long as he was able to give the arm affected the rest it needed.

Rin was about as much of a worrywart as he’d anticipated, when he finally did confront him on the matter. It’d been hard to hide the fact that there was something wrong in normal school, and so Suguro had noticed, and since the cram school students – apart from Izumo and Takara – often had lunch together, Rin must have found out that way.

“Yeesh, Yukio. I mean, I get you go on dangerous missions and all, but tell me when something like this happens! I’m your big brother, aren’t I? I should know about this kind of stuff!”

He’d smiled, and nodded, and admitted that maybe he should have been more open… in this case, at least.

The scratches started to itch that night, but he took it to mean that they were healing, and resolved to change the bandages the next day.

He did, but he also had yet another mission, less strenuous this time, but still enough to keep him busy when he wasn’t in school hours. At least here the school understood that if he was late for class or had to leave early, he wasn’t actually ill, and he didn’t have to make the excuse that he was.

Of course, the fact that he _was_ currently injured was beside the point. He could still keep up with his classes, be useful on missions, and file his reports, and that was what mattered, in the end.

It was then, when he’d just started to think that things were going to be all right, that the first sign came.

He found himself dreaming of running in the night, of reaching out for something that wasn’t there, not yet, just and only just out of reach… and the light of something shining in the corner of his eye, calling to him.

He woke up feeling a lingering longing that scared him, because while he often had nightmares and strange dreams, this didn’t fit the normal form of things.

He hoped, at first, that if he ignored it that it would go away.

He should have known that it was a fool’s hope, and the next day he dreamed of the same things. And the day after.

By the day after that, and running a slight temperature, he realised that there was nothing else to it. He’d have to accept that these might be signs of something worse.

Far worse than he’d previously been dreading, he found out when he finally went to see a doctor about it.

He should have come sooner, they said. The vaccine had, against the odds, not worked. The curse had been allowed to pass on to him, and this type of demon especially was known to be dangerous.

He should have come sooner.

In not wanting to accept that one thing might have a hold over him, he had allowed something else in.

It had already been a little over a week, and another passed with him being increasingly busy, and increasingly unwilling to face up to what would have to be done. But in the end, the preparations were made, and there would be no turning back.

He lasted until the week before the full moon, and then there was no choice. After informing the other teachers of his condition, he told the students what was happening to him.

That he would be unable to teach for those three nights he would be affected. Potentially, during the daytime as well.

And that should he become a danger in any way, they should deal with him accordingly.

The exwires reacted as was expected by now – shock, but also horror, and the denial that they would be able to react the way their teacher wanted them to in such a situation, especially from Rin, Suguro… and Shiemi.

He had told them sharply that if they wanted to live, and wanted to not be seen as dangers due to their own choice of inaction, then they would do as instructed. Or not have any say in the matter at all.

After that, tensions rose in anxious anticipation. It was especially noticeable with Rin, since they were sharing a dorm together, and to describe his brother’s attitude as ‘angry’ didn’t cut it, but neither did ‘worried’. It was something more, and Rin wasn’t afraid to let it show, and frequently.

He spent the last day feeling ill, and he couldn’t tell whether it was due to whatever changes were still going on in his body and spirit, or merely nerves for the inevitable.

He excused himself from classes early, in order to make sure the preparations were all in order, to make sure that nothing could go wrong, and that everyone was prepared.

It had been decided that the exwires would be in attendance, and he couldn’t entirely fault the reasoning. Together, they had great ability, if they’d only learn to utilise it properly, and his brother, if it should come to that, would be one of the few who could take him down without any danger to either of them.

When the time came, he let himself into the cage that had been given over for his purpose, gave Tsubaki the key, and sat down on the bench, the only thing in the cell, to wait.

…

As the sun set, Rin couldn’t stay still.

He hadn’t been able to all day, for that matter.  Whereas normally he’d be falling asleep in class, today, and the past few days, really, he’d been unable to relax enough to drop off, even during his most boring and his hardest classes.

That wasn’t to say he’d been paying any _attention._ He’d just not been able to focus.

This was his little brother, after all. His little brother, who hadn’t told him anything – all right, hadn’t told him _enough_ – about what was going on, who was sat in a _cage_ now…

It wasn’t his fault. And no one was putting the blame on anyone. Even the higher-ups allowed that as long as he was kept safe and secure while he was dangerous and not allowed to let harm come to anyone, it wouldn’t be a problem, and life could continue as normal.

Rin didn’t _care_.  He’d been, what, asleep, when it’d happened?

And now, all he could do was pace, and tug at his already messy enough hair, puffs of flame licking at him. The others didn’t even spare it a glance.

Most of them were just sitting there, tense and with worried expressions. He couldn’t blame them.

After all, they couldn’t _do_ anything.

He made a noise of frustration, and Shiemi looked up at him, Nii-chan looking just as worried as she was.

“Rin…”

He wanted to smile and pretend everything was going to be okay, but it wasn’t, because that was _Yukio_ …

He stilled without warning, tail stopping in its tracks, eyes darting unerringly to where Yukio was.

“It’s started, hasn’t it?”

Suguro was just as grim, a scowl belying how much he actually cared, beads in his hands even if they weren’t likely to be used.

Rin nodded, and slid his back down the wall to sit right where he was, knees up to his chest and tail  curled around his legs.

There wasn’t really much to say after that.

The silence was awkward. Made more so by the fact that anything anyone might have ordinarily done to idle away the time seemed outright disrespectful now, from chanting sutras or verses that might inadvertently harm their teacher, to a phone call that was, for once, turned down.

Minutes ticked by. Rin took his phone out to check the time, only to find that it hadn’t been more than an hour since it’d started.

He was putting his phone away when it started.

“Did you say something?”

The others shook their heads.

He frowned, though, _sure_ that he’d heard something. Maybe it was just him, but… he didn’t think so.

His tail began to twitch again. Just the tip, creating small swishing and light thumping noises against the floor.

He willed it to still, and… heard that noise again.

“Damn it, I _know_ I heard something that time!”

He stood up, which allowed his tail more freedom of movement, and he was halfway down the corridor before they could stop him.

“O-oi! Okumura, get your ass back here!”

“I’m not gonna do anything stupid, so you can just can it! I was definitely hearing things, and there’s only thing here that could be making noises!”

And that, of course, was Yukio. Even if it wasn’t _Yukio_ , it was still his brother they were dealing with. He had to know what was happening. What was going on.

He heard the scraping of chairs and feet on the floor, the others coming after him.

And there it was again. That _sound_. Like a door hinge had come loose… but none of the doors were open.

In fact, it was coming from the _cage_ …

“Hey…” The look of irritated frustration on Suguro’s face had shifted into one of confusion. “Doesn’t that sound kinda…”

It happened again, and Shima snorted, but the gravity of the situation put Rin in mind of how the guy hadn’t been able to hold a straight face even against Amaimon, when the demon king had been given a broccoli hairdo.

But what was funny about this?

The sound came again, a sort of whining, and Konekomaru’s eyes widened, as though he’d realised something.

“You’re right! Like a, a…”

They inched closer.

“Hey, be _careful!”_

But it was too late. They were already just outside of the cell’s door, well within reach should something have wanted to lash out at them.

The thing was, nothing _did_.

In fact it took a few moments until that noise returned, and it really was like Konekomaru and Suguro had said – like a dog whining. Or rather… more like a _puppy_.

Rin wasted no time in trying to look for the source – he couldn’t see Yukio anywhere, or even any sort of wolf, which he assumed Yukio was right now. It wasn’t _too_ dark in there, since the hall itself was lit, but…

He got down out of either a gut feeling or suspicion, and looked underneath the bench.

A pair of green eyes, completely the wrong shape but undeniably _Yukio’s_ because they held the same red light in them as Rin’s own, looked back at him.

Maybe it was a foolish wish, but he _smiled_ , because that didn’t seem like a demon had possessed his brother at all. Something had happened, sure, but that was _him_ in there.

“Er… Okumura? Any idea what’s goin’ on here?”

“Yukio isn’t possessed,” he said firmly. “He’s scared!”

“Uh… what?”

“Look at him! Does that seem like a terrifying demon to you?”

Suguro knelt down to have a better look, but when he did so the whining intensified and there was a slight scrabbling noise as well.

“The hell?”

Shima sniggered.   “Maybe wolf-sensei’s scared of your hair, bon!”

Rin found himself trying not to laugh, and he heard an odd sound – when he turned away for a moment, it looked like Shiemi was smiling, too. But in the end, he turned back to the cage, and his brother.

“Hey, Yukio. ‘S all right. C’mon.”

“O-Okumura-kun you really shouldn’t-!”

Tsubaki was, again, summarily ignored. Their teacher was relegated to hovering somewhat nervously in the background as the wolf emerged, if slowly, from under the bench.

Yukio had mostly dark brown fur, with several darker patches over his face, as far as he could tell. He was also small, or smaller than they’d been expecting, with his ears flat against the back of his head, clearly on edge.

Yukio’s eyes darted from person to person before finding Rin again and inching forward further toward the gate by increments.

When, finally, he was close enough to stick a paw through, he didn’t. Instead, Rin found himself holding out a hand – and when the others objected, he told them that he was already a demon, it was hardly as though he could be infected or cursed, and if he was hurt, he’d just heal from it.

But instead of being bitten, his hand felt suddenly cold.

He looked down, only to find Yukio licking his fingers.

“Er, sensei?” Rin heard Shima saying. “I think something went wrong on the whole ‘Okumura-sensei turning into a dangerous, demonic beast’ thing, don’t ya think?”

Rin, meanwhile, was quickly finding out that yes, it was indeed Suguro’s hair that was freaking Yukio out for the moment, even though this wolf form of his brother seemed to be skittish around everyone no matter what.

...

AN: I put 'multiple chapters' in because... well, I've been discussing this a lot over on Tumblr, and there's a fair few other scenes that I think I'd like to cover.

It also fits as an AU instead of just a fic idea because it's got a clear timeframe - some time before Rin meets/befriends Godaiin. Meaning that I've been having fun plotting out how future scenes will be with Yukio as a werewolf.  Although that said, some things may only fit into comic book continuity (extending the timeframe), since the amount of time we're given doesn't always give enough for everything in the story I'd want to _tell_.

Pairings aren't tagged yet as so far they're all unconfirmed, but if it becomes apparent, I'll tag them. For those who'd like to know, so far it's either gen/no pairings, or canon relationships. If they find their way into the fic, it'll probably be Yukio/Shiemi and Rin/Izumo. I can't help it. Others may be hinted at too, though.

\--As an aside, I've got a thing on Tumblr that since someone was interested in writing for the AU before I wrote this, people should feel free to use the ideas I post up in the 'werewolf Yukio' tag. Anything done for it will be linked into a post so that everyone can see it.


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